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Ma H, Kennard A, Mattson N, Khan AS. Characterization of Sf9 cell clones with differential susceptibilities to Sf-rhabdovirus X +3.7 and Sf-rhabdovirus X - replication. Virology 2024; 594:110038. [PMID: 38471199 DOI: 10.1016/j.virol.2024.110038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 02/16/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024]
Abstract
Our laboratory previously discovered a novel rhabdovirus in the Spodoptera frugiperda Sf9 insect cell line that was designated as Sf-rhabdovirus. Using limiting dilution, this cell line was found to be a mixed population of cells infected by Sf-rhabdovirus variants containing either the full length X accessory gene with a 3.7 kb internal duplication (designated as Sf-rhabdovirus X+3.7) or lacking the duplication and part of the X gene (designated as Sf-rhabdovirus X-), and cells that were negative for Sf-rhabdovirus. In this paper, we found that the Sf-rhabdovirus negative cell clones had sub-populations with different susceptibilities to the replication of Sf-rhabdovirus X+3.7 and X- variants: cell clone Sf9-13F12 was more sensitive to replication by both virus variants compared to Sf9-3003; moreover, Sf9-3003 showed more resistance to X+3.7 replication than to X- replication. RNA-Seq analysis indicated significant differentially expressed genes in the Sf9-13F12 and Sf9-3003 cell clones further supporting that distinct sub-populations of virus-negative cells co-exist in the parent Sf9 cell line.
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Affiliation(s)
- Hailun Ma
- Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Andrea Kennard
- Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Nicholas Mattson
- Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Arifa S Khan
- Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA.
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Menzies SK, Arinto-Garcia R, Amorim FG, Cardoso IA, Abada C, Crasset T, Durbesson F, Edge RJ, El-Kazzi P, Hall S, Redureau D, Stenner R, Boldrini-França J, Sun H, Roldão A, Alves PM, Harrison RA, Vincentelli R, Berger I, Quinton L, Casewell NR, Schaffitzel C. ADDovenom: Thermostable Protein-Based ADDomer Nanoparticles as New Therapeutics for Snakebite Envenoming. Toxins (Basel) 2023; 15:673. [PMID: 38133177 PMCID: PMC10747859 DOI: 10.3390/toxins15120673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/13/2023] [Accepted: 11/23/2023] [Indexed: 12/23/2023] Open
Abstract
Snakebite envenoming can be a life-threatening medical emergency that requires prompt medical intervention to neutralise the effects of venom toxins. Each year up to 138,000 people die from snakebites and threefold more victims suffer life-altering disabilities. The current treatment of snakebite relies solely on antivenom-polyclonal antibodies isolated from the plasma of hyperimmunised animals-which is associated with numerous deficiencies. The ADDovenom project seeks to deliver a novel snakebite therapy, through the use of an innovative protein-based scaffold as a next-generation antivenom. The ADDomer is a megadalton-sized, thermostable synthetic nanoparticle derived from the adenovirus penton base protein; it has 60 high-avidity binding sites to neutralise venom toxins. Here, we outline our experimental strategies to achieve this goal using state-of-the-art protein engineering, expression technology and mass spectrometry, as well as in vitro and in vivo venom neutralisation assays. We anticipate that the approaches described here will produce antivenom with unparalleled efficacy, safety and affordability.
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Affiliation(s)
- Stefanie K. Menzies
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
- Centre for Drugs & Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Raquel Arinto-Garcia
- iBET, Instituto de Biologia Experimental e Technológica, Apartado 12, 2781-901 Oeiras, Portugal
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Fernanda Gobbi Amorim
- Mass Spectrometry Laboratory, MolSys Research Unit, Allée du six Aout 11, Quartier Agora, Liège Université, 4000 Liège, Belgium
| | - Iara Aimê Cardoso
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Camille Abada
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Thomas Crasset
- Mass Spectrometry Laboratory, MolSys Research Unit, Allée du six Aout 11, Quartier Agora, Liège Université, 4000 Liège, Belgium
| | - Fabien Durbesson
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille Université, 13009 Marseille, France
| | - Rebecca J. Edge
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Priscila El-Kazzi
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille Université, 13009 Marseille, France
| | - Sophie Hall
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
- Max Planck Bristol Centre for Minimal Biology, Cantock’s Close, Bristol BS8 1TS, UK
| | - Damien Redureau
- Mass Spectrometry Laboratory, MolSys Research Unit, Allée du six Aout 11, Quartier Agora, Liège Université, 4000 Liège, Belgium
| | - Richard Stenner
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
- Max Planck Bristol Centre for Minimal Biology, Cantock’s Close, Bristol BS8 1TS, UK
| | - Johara Boldrini-França
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
- Max Planck Bristol Centre for Minimal Biology, Cantock’s Close, Bristol BS8 1TS, UK
| | - Huan Sun
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
- Max Planck Bristol Centre for Minimal Biology, Cantock’s Close, Bristol BS8 1TS, UK
| | - António Roldão
- iBET, Instituto de Biologia Experimental e Technológica, Apartado 12, 2781-901 Oeiras, Portugal
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Paula M. Alves
- iBET, Instituto de Biologia Experimental e Technológica, Apartado 12, 2781-901 Oeiras, Portugal
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Robert A. Harrison
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
- Centre for Drugs & Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Renaud Vincentelli
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille Université, 13009 Marseille, France
| | - Imre Berger
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
- Max Planck Bristol Centre for Minimal Biology, Cantock’s Close, Bristol BS8 1TS, UK
| | - Loïc Quinton
- Mass Spectrometry Laboratory, MolSys Research Unit, Allée du six Aout 11, Quartier Agora, Liège Université, 4000 Liège, Belgium
| | - Nicholas R. Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
- Centre for Drugs & Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Christiane Schaffitzel
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
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Menghini MT, Geisler C, Maghodia AB, Hallam HJ, Denton SL, Gigley JP, Jarvis DL. Host ranges of Sf-rhabdoviruses harbored by lepidopteran insects and insect cell lines. Virology 2023; 585:164-178. [PMID: 37348145 PMCID: PMC10528406 DOI: 10.1016/j.virol.2023.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/16/2023] [Accepted: 05/22/2023] [Indexed: 06/24/2023]
Abstract
Cell lines derived from Spodoptera frugiperda (Sf), which are the most widely used hosts in the baculovirus-insect cell system, are contaminated with Sf-rhabdoviruses (Sf-RVs). In this study, we identified a closely related virus (Sf-CAT-RV) in the caterpillar species used to isolate the original Sf cell line. We then evaluated the Sf-RV and Sf-CAT-RV host ranges, found Sf-CAT-RV could infect Vero cells, and obtained results suggesting both variants can infect mouse ear fibroblasts. In addition, we found both variants could establish pantropic infections in severely immunocompromised (RAG2/IL2RG-/-) mice. However, both variants were cleared by two weeks post-inoculation and neither produced any symptoms or obvious adverse outcomes in these hosts. We conclude the caterpillars used to isolate Sf21 cells were the most likely source of the Sf-RV contaminant, Sf-RVs and their Sf-CAT-RV progenitor have broader host ranges than expected from previous work, but neither variant poses a serious threat to human health.
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Affiliation(s)
- Mark T Menghini
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
| | | | | | | | - Steven L Denton
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
| | - Jason P Gigley
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
| | - Donald L Jarvis
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA; GlycoBac, LLC, Laramie, WY, USA.
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de Malmanche H, Hussain M, Marcellin E, Reid S, Asgari S. Knockout of Dicer-2 in the Sf9 cell line enhances the replication of Spodoptera frugiperda rhabdovirus and conditionally increases baculovirus replication. J Gen Virol 2022; 103. [PMID: 36018884 DOI: 10.1099/jgv.0.001779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Sf9 cell line, originally isolated from the ovarian tissue of Spodoptera frugiperda larvae, is widely used in academia and industry for the baculovirus-mediated production of recombinant proteins and virus-like particles. RNA interference (RNAi) is a conserved antiviral pathway present in eukaryotic organisms and is the primary antiviral defence mechanism in insects. Recent evidence has implicated RNAi as an antiviral response to baculovirus infection in Sf9 cells. To test this hypothesis, CRISPR/Cas9 technology was used to disable the RNAi pathway in Sf9 cells by knocking out Dicer-2, the protein responsible for cleaving viral double-stranded RNA precursors into short interfering RNAs. Infection of Dicer-2 knockout Sf9 cells with either the wild-type baculovirus Autographa californica nucleopolyhedrovirus (AcMNPV), recombinant AcMNPV (rAcMNPV) expressing β-galactosidase (β-gal), or rAcMNPV expressing a wasp venom protein (Vn50) at a multiplicity of infection (m.o.i.) of 1 resulted in a modest increase in virus replication compared to control Sf9 cells under adherent culture conditions. In contrast, Dicer-2 knockout Sf9 monolayer or suspension cultures infected by the rAcMNPV expressing β-gal at higher m.o.i.s (3.5 and 20) did not exhibit increases in either viral DNA replication or β-gal production. Intriguingly, during long-term passaging in suspension, Dicer-2 knockout Sf9 cultures underwent transient crashes in cell proliferation and viability. It was discovered that these periods of low growth and viability coincided with a dramatic increase in the RNA levels of S. frugiperda rhabdovirus, a recently identified adventitious virus that persistently infects the Sf9 cell line, suggesting a role for Dicer-2 in managing chronic viral infections in this industrially relevant insect cell line.
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Affiliation(s)
- Henry de Malmanche
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Mazhar Hussain
- School of Biological Sciences, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Steve Reid
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Sassan Asgari
- School of Biological Sciences, The University of Queensland, St Lucia, QLD 4072, Australia
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Iwata S, Sonoyama T, Kamitani A, Shibata R, Homma T, Omoto S, Igarashi K, Ariyasu M. Phase 1/2 clinical trial of COVID-19 vaccine in Japanese participants: A report of interim findings. Vaccine 2022; 40:3721-3726. [PMID: 35606235 PMCID: PMC9122779 DOI: 10.1016/j.vaccine.2022.04.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/09/2022] [Accepted: 04/14/2022] [Indexed: 11/27/2022]
Abstract
We initiated a randomized, placebo-controlled, phase 1/2 trial to evaluate the safety and immunogenicity of the S-268019-b recombinant protein vaccine, scheduled as 2 intramuscular injections given 21 days apart, in 60 randomized healthy Japanese adults. We evaluated 2 regimens of the S-910823 antigen (5 μg [n = 24] and 10 μg [n = 24]) with an oil-in-water emulsion formulation and compared against placebo (n = 12). Reactogenicity was mild in most participants. No serious adverse events were noted. For both regimens, vaccination resulted in robust IgG and neutralizing antibody production at days 36 and 50 and predominant T-helper 1-mediated immune reaction, as evident through antigen-specific polyfunctional CD4+ T-cell responses with IFN-γ, IL-2, and IL-4 production on spike protein peptides stimulation. Based on the interim analysis, the S-268019-b vaccine is safe, produces neutralizing antibodies titer comparable with that in convalescent serum from COVID-19-recovered patients. However, further evaluation of the vaccine in a large clinical trial is warranted.
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Mabashi-Asazuma H, Jarvis DL. A new insect cell line engineered to produce recombinant glycoproteins with cleavable N-glycans. J Biol Chem 2021; 298:101454. [PMID: 34838817 PMCID: PMC8689212 DOI: 10.1016/j.jbc.2021.101454] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/16/2021] [Accepted: 11/21/2021] [Indexed: 01/09/2023] Open
Abstract
Glycoproteins are difficult to crystallize because they have heterogeneous glycans composed of multiple monosaccharides with considerable rotational freedom about their O-glycosidic linkages. Crystallographers studying N-glycoproteins often circumvent this problem by using β1,2-N-acetylglucosaminyltransferase I (MGAT1)–deficient mammalian cell lines, which produce recombinant glycoproteins with immature N-glycans. These glycans support protein folding and quality control but can be removed using endo-β-N-acetylglucosaminidase H (Endo H). Many crystallographers also use the baculovirus-insect cell system (BICS) to produce recombinant proteins for their work but have no access to an MGAT1-deficient insect cell line to facilitate glycoprotein crystallization in this system. Thus, we used BICS-specific CRISPR–Cas9 vectors to edit the Mgat1 gene of a rhabdovirus-negative Spodoptera frugiperda cell line (Sf-RVN) and isolated a subclone with multiple Mgat1 deletions, which we named Sf-RVNLec1. We found that Sf-RVN and Sf-RVNLec1 cells had identical growth properties and served equally well as hosts for baculovirus-mediated recombinant glycoprotein production. N-glycan profiling showed that a total endogenous glycoprotein fraction isolated from Sf-RVNLec1 cells had only immature and high mannose-type N-glycans. Finally, N-glycan profiling and endoglycosidase analyses showed that the vast majority of the N-glycans on three recombinant glycoproteins produced by Sf-RVNLec1 cells were Endo H-cleavable Man5GlcNAc2 structures. Thus, this study yielded a new insect cell line for the BICS that can be used to produce recombinant glycoproteins with Endo H-cleavable N-glycans. This will enable researchers to combine the high productivity of the BICS with the ability to deglycosylate recombinant glycoproteins, which will facilitate efforts to determine glycoprotein structures by X-ray crystallography.
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Affiliation(s)
| | - Donald L Jarvis
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming, USA; GlycoBac, LLC, Laramie, Wyoming, USA.
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7
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Maghodia AB, Geisler C, Jarvis DL. A New Bacmid for Customized Protein Glycosylation Pathway Engineering in the Baculovirus-Insect Cell System. ACS Chem Biol 2021; 16:1941-1950. [PMID: 33596046 DOI: 10.1021/acschembio.0c00974] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
One attractive feature of the baculovirus-insect cell system (BICS) is the baculoviral genome has a large capacity for genetic cargo. This enables construction of viral vectors designed to accept multigene insertions, which has facilitated efforts to produce recombinant multisubunit protein complexes. However, the large genetic capacity of baculovirus vectors has not yet been exploited for multistep pathway engineering. Therefore, we created PolyBac, which is a novel baculovirus shuttle vector, or bacmid, that can be used for this purpose. PolyBac was designed to accept multiple transgene insertions by three different mechanisms at three different sites within the baculovirus genome. After constructing and characterizing PolyBac, we used it to isolate nine derivatives encoding various combinations of up to eight different protein N-glycosylation pathway functions, or glycogenes. We then used these derivatives, which were designed to progressively extend the endogenous insect cell pathway, to assess PolyBac's utility for protein glycosylation pathway engineering. This assessment was enabled by engineering each derivative to produce a recombinant influenza hemagglutinin (rH5), which was used to probe the impact of each glycoengineered PolyBac derivative on the endogenous insect cell pathway. Genetic analyses of these derivatives confirmed PolyBac can accept large DNA insertions. Biochemical analyses of the rH5 products showed each had distinct N-glycosylation profiles. Finally, the major N-glycan on each rH5 product was the predicted end product of the engineered N-glycosylation pathways encoded by each PolyBac derivative. These results generally indicate that PolyBac has utility for multistep metabolic pathway engineering and directly demonstrate that this new bacmid can be used for customized protein glycosylation pathway engineering in the BICS.
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Affiliation(s)
| | | | - Donald L. Jarvis
- GlycoBac, LLC, Laramie, Wyoming 82072, United States
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071, United States
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Structural and Biophysical Characterization of the HCV E1E2 Heterodimer for Vaccine Development. Viruses 2021; 13:v13061027. [PMID: 34072451 PMCID: PMC8227786 DOI: 10.3390/v13061027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 02/07/2023] Open
Abstract
An effective vaccine for the hepatitis C virus (HCV) is a major unmet medical and public health need, and it requires an antigen that elicits immune responses to multiple key conserved epitopes. Decades of research have generated a number of vaccine candidates; based on these data and research through clinical development, a vaccine antigen based on the E1E2 glycoprotein complex appears to be the best choice. One bottleneck in the development of an E1E2-based vaccine is that the antigen is challenging to produce in large quantities and at high levels of purity and antigenic/functional integrity. This review describes the production and characterization of E1E2-based vaccine antigens, both membrane-associated and a novel secreted form of E1E2, with a particular emphasis on the major challenges facing the field and how those challenges can be addressed.
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Joshi PRH, Venereo-Sanchez A, Chahal PS, Kamen AA. Advancements in molecular design and bioprocessing of recombinant adeno-associated virus gene delivery vectors using the insect-cell baculovirus expression platform. Biotechnol J 2021; 16:e2000021. [PMID: 33277815 DOI: 10.1002/biot.202000021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 11/27/2020] [Indexed: 01/23/2023]
Abstract
Despite rapid progress in the field, scalable high-yield production of adeno-associated virus (AAV) is still one of the critical bottlenecks the manufacturing sector is facing. The insect cell-baculovirus expression vector system (IC-BEVS) has emerged as a mainstream platform for the scalable production of recombinant proteins with clinically approved products for human use. In this review, we provide a detailed overview of the advancements in IC-BEVS for rAAV production. Since the first report of baculovirus-induced production of rAAV vector in insect cells in 2002, this platform has undergone significant improvements, including enhanced stability of Bac-vector expression and a reduced number of baculovirus-coinfections. The latter streamlining strategy led to the eventual development of the Two-Bac, One-Bac, and Mono-Bac systems. The one baculovirus system consisting of an inducible packaging insect cell line was further improved to enhance the AAV vector quality and potency. In parallel, the implementation of advanced manufacturing approaches and control of critical processing parameters have demonstrated promising results with process validation in large-scale bioreactor runs. Moreover, optimization of the molecular design of vectors to enable higher cell-specific yields of functional AAV particles combined with bioprocess intensification strategies may also contribute to addressing current and future manufacturing challenges.
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Affiliation(s)
- Pranav R H Joshi
- Department of Bioengineering, McGill University, Montréal, Quebec, Canada
| | | | - Parminder S Chahal
- Human Health Therapeutics Portfolio, National Research Council of Canada, Montréal, Quebec, Canada
| | - Amine A Kamen
- Department of Bioengineering, McGill University, Montréal, Quebec, Canada
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10
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Maghodia AB, Geisler C, Jarvis DL. A new nodavirus-negative Trichoplusia ni cell line for baculovirus-mediated protein production. Biotechnol Bioeng 2020; 117:3248-3264. [PMID: 32662870 DOI: 10.1002/bit.27494] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/21/2020] [Accepted: 07/12/2020] [Indexed: 12/22/2022]
Abstract
Cell lines derived from Trichoplusia ni (Tn) are widely used as hosts in the baculovirus-insect cell system (BICS). One advantage of Tn cell lines is they can produce recombinant proteins at higher levels than cell lines derived from other insects. However, Tn cell lines are persistently infected with an alphanodavirus, Tn5 cell-line virus (TnCLV), which reduces their utility as a host for the BICS. Several groups have isolated TnCLV-negative Tn cell lines, but none were thoroughly characterized and shown to be free of other adventitious viruses. Thus, we isolated and extensively characterized a new TnCLV-negative line, Tn-nodavirus-negative (Tn-NVN). Tn-NVN cells have no detectable TnCLV, no other previously identified viral contaminants of lepidopteran insect cell lines, and no sequences associated with any replicating virus or other viral adventitious agents. Tn-NVN cells tested negative for >60 species of Mycoplasma, Acholeplasma, Spiroplasma, and Ureaplasma. Finally, Tn-NVN cells grow well as a single-cell suspension culture in serum-free medium, produce recombinant proteins at levels similar to High Five™ cells, and do not produce recombinant glycoproteins with immunogenic core α1,3-fucosylation. Thus, Tn-NVN is a new, well-characterized TnCLV-negative cell line with several other features enhancing its utility as a host for the BICS.
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Affiliation(s)
| | | | - Donald L Jarvis
- GlycoBac, LLC, Laramie, Wyoming.,Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
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11
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Ma H, Nandakumar S, Bae EH, Chin PJ, Khan AS. The Spodoptera frugiperda Sf9 cell line is a heterogeneous population of rhabdovirus-infected and virus-negative cells: Isolation and characterization of cell clones containing rhabdovirus X-gene variants and virus-negative cell clones. Virology 2019; 536:125-133. [PMID: 31494355 DOI: 10.1016/j.virol.2019.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 11/28/2022]
Abstract
The Sf9 cell line is broadly used for manufacturing baculovirus-expressed viral vaccines. We previously reported the presence of a novel, rhabdovirus in the Sf9 cell line, which contained a unique X gene (Sf-rhabdovirus; designated as X+ in this paper). These results were extended by other reports describing an Sf-rhabdovirus variant in Sf9 cells, which lacked 320 nucleotides encompassing the X-gene and adjacent intergenic region (designated as X- in this paper), and the development of an Sf-rhabdovirus negative cell line. Here, we report that the Sf9 cell line is a mixed-cell population, based upon isolation of cell clones with distinct phenotypes: Sf-rhabdovirus-negative, X+, and X-. We also show that Sf-rhabdovirus X+ and X- variants replicate independently in Sf-rhabdovirus-negative cells. These results shed light on the detection of different rhabdovirus variants by different laboratories using Sf9-derived cell clones and confirm that both X+ and X- viruses are infectious in rhabdovirus-negative Sf9 cells.
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Affiliation(s)
- Hailun Ma
- Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Subhiksha Nandakumar
- Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Eunhae H Bae
- Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Pei-Ju Chin
- Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Arifa S Khan
- Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA.
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12
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Amann T, Schmieder V, Faustrup Kildegaard H, Borth N, Andersen MR. Genetic engineering approaches to improve posttranslational modification of biopharmaceuticals in different production platforms. Biotechnol Bioeng 2019; 116:2778-2796. [PMID: 31237682 DOI: 10.1002/bit.27101] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/27/2019] [Accepted: 06/18/2019] [Indexed: 12/18/2022]
Abstract
The number of approved biopharmaceuticals, where product quality attributes remain of major importance, is increasing steadily. Within the available variety of expression hosts, the production of biopharmaceuticals faces diverse limitations with respect to posttranslational modifications (PTM), while different biopharmaceuticals demand different forms and specifications of PTMs for proper functionality. With the growing toolbox of genetic engineering technologies, it is now possible to address general as well as host- or biopharmaceutical-specific product quality obstacles. In this review, we present diverse expression systems derived from mammalians, bacteria, yeast, plants, and insects as well as available genetic engineering tools. We focus on genes for knockout/knockdown and overexpression for meaningful approaches to improve biopharmaceutical PTMs and discuss their applicability as well as future trends in the field.
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Affiliation(s)
- Thomas Amann
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Valerie Schmieder
- acib GmbH-Austrian Centre of Industrial Biotechnology, Graz, Austria.,Department of Biotechnology, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
| | - Helene Faustrup Kildegaard
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Nicole Borth
- Department of Biotechnology, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
| | - Mikael Rørdam Andersen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
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Host Range and Population Survey of Spodoptera frugiperda Rhabdovirus. J Virol 2019; 93:JVI.02028-18. [PMID: 30626676 DOI: 10.1128/jvi.02028-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 12/18/2018] [Indexed: 11/20/2022] Open
Abstract
The Sf9 and Sf21 cell lines derived from ovarian tissues of the wide-host-range phytophagous lepidopteran Spodoptera frugiperda are widely used for research and commercial-scale production of recombinant proteins. These cell lines are chronically infected with a rhabdovirus (Sf-RV) that does not cause any overt cytopathic effects. We demonstrate that wild populations of S. frugiperda in the eastern United States and Caribbean are infected with genetically diverse strains of Sf-RV and that this virus is also capable of infecting cells of Spodoptera exigua, Heliothis subflexa, and Bombyx mori Feeding studies demonstrated the ability of S. frugiperda larvae to deposit Sf-RV onto human-consumed vegetables during feeding. Although no evidence for replication in two species of plant cells was detected, subcellular localization studies demonstrated that the Sf-RV nucleocapsid was targeted to plasmodesmata, while two forms of the accessory protein were differentiated on the basis of their ability to localize to nuclei. Collectively, the results from this study suggest that environmental exposure of humans to Sf-RV is likely to be commonplace and frequent, but its inability to replicate in plant or human cells suggests that there is no substantial risk to human health.IMPORTANCE Insect-derived cell lines are widely used commercially for the production of vaccines and protein-based pharmaceuticals. After decades of safe and beneficial use, it was a surprise to the biotechnology industry to discover an endemic rhabdovirus in Sf9 cells. This discovery was made possible only by the substantial advancements in DNA sequencing technologies. Given the public health concerns associated with many rhabdovirus species, several initiatives were undertaken to establish that Spodoptera frugiperda rhabdovirus (Sf-RV) does not pose a threat to humans. Such actions include the generation of cell lines that have been cleared of Sf-RV. Given that Sf9 is derived from a moth whose larvae feed on human-edible foods, we explored the prevalence of Sf-RV in its wild and lab-grown populations, as well as its ability to be deposited on food items during feeding. Collectively, our data suggest that there is no overt risk from exposure to Sf-RV.
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Kaczmarek R. Do adventitious viruses carried by insect cell lines producing AAV vectors pose a safety risk in gene therapy? Haemophilia 2018; 24:843-844. [DOI: 10.1111/hae.13525] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2018] [Indexed: 12/17/2022]
Affiliation(s)
- R. Kaczmarek
- Hirszfeld Institute of Immunology and Experimental Therapy; Wroclaw Poland
- Polish Hemophilia Society; Warsaw Poland
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15
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Geisler C. A new approach for detecting adventitious viruses shows Sf-rhabdovirus-negative Sf-RVN cells are suitable for safe biologicals production. BMC Biotechnol 2018; 18:8. [PMID: 29415704 PMCID: PMC5803895 DOI: 10.1186/s12896-017-0412-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/28/2017] [Indexed: 01/01/2023] Open
Abstract
Background Adventitious viral contamination in cell substrates used for biologicals production is a major safety concern. A powerful new approach that can be used to identify adventitious viruses is a combination of bioinformatics tools with massively parallel sequencing technology. Typically, this involves mapping or BLASTN searching individual reads against viral nucleotide databases. Although extremely sensitive for known viruses, this approach can easily miss viruses that are too dissimilar to viruses in the database. Moreover, it is computationally intensive and requires reference cell genome databases. To avoid these drawbacks, we set out to develop an alternative approach. We reasoned that searching genome and transcriptome assemblies for adventitious viral contaminants using TBLASTN with a compact viral protein database covering extant viral diversity as the query could be fast and sensitive without a requirement for high performance computing hardware. Results We tested our approach on Spodoptera frugiperda Sf-RVN, a recently isolated insect cell line, to determine if it was contaminated with one or more adventitious viruses. We used Illumina reads to assemble the Sf-RVN genome and transcriptome and searched them for adventitious viral contaminants using TBLASTN with our viral protein database. We found no evidence of viral contamination, which was substantiated by the fact that our searches otherwise identified diverse sequences encoding virus-like proteins. These sequences included Maverick, R1 LINE, and errantivirus transposons, all of which are common in insect genomes. We also identified previously described as well as novel endogenous viral elements similar to ORFs encoded by diverse insect viruses. Conclusions Our results demonstrate TBLASTN searching massively parallel sequencing (MPS) assemblies with a compact, manually curated viral protein database is more sensitive for adventitious virus detection than BLASTN, as we identified various sequences that encoded virus-like proteins, but had no similarity to viral sequences at the nucleotide level. Moreover, searches were fast without requiring high performance computing hardware. Our study also documents the enhanced biosafety profile of Sf-RVN as compared to other Sf cell lines, and supports the notion that Sf-RVN is highly suitable for the production of safe biologicals. Electronic supplementary material The online version of this article (doi: 10.1186/s12896-017-0412-z) contains supplementary material, which is available to authorized users.
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Geisler C, Jarvis DL. Adventitious viruses in insect cell lines used for recombinant protein expression. Protein Expr Purif 2017; 144:25-32. [PMID: 29133148 DOI: 10.1016/j.pep.2017.11.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 11/08/2017] [Indexed: 11/16/2022]
Abstract
Insect cells are widely used for recombinant protein expression, typically as hosts for recombinant baculovirus vectors, but also for plasmid-mediated transient transfection or stable genetic transformation. Insect cells are used to express proteins for research, as well as to manufacture biologicals for human and veterinary medicine. Recently, several insect cell lines used for recombinant protein expression were found to be persistently infected with adventitious viruses. This has raised questions about how these infections might affect research performed using those cell lines. Furthermore, these findings raised serious concerns about the safety of biologicals produced using those cell lines. In response, new insect cell lines lacking adventitious viruses have been isolated for use as improved research tools and safer biological manufacturing platforms. Here, we review the scientific and patent literature on adventitious viruses found in insect cell lines, affected cell lines, and new virus-free cell lines.
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Affiliation(s)
| | - Donald L Jarvis
- GlycoBac LLC, 1938 Harney Street, Laramie, WY 82072, USA; University of Wyoming, Department of Molecular Biology, 1000 E. University Avenue, Laramie, WY 82071, USA
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17
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Maghodia AB, Jarvis DL. Infectivity of Sf-rhabdovirus variants in insect and mammalian cell lines. Virology 2017; 512:234-245. [PMID: 29024851 DOI: 10.1016/j.virol.2017.09.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 09/27/2017] [Accepted: 09/30/2017] [Indexed: 12/31/2022]
Abstract
Sf-rhabdovirus was only recently identified as an adventitious agent of Spodoptera frugiperda (Sf) cell lines used as hosts for baculovirus vectors. As such, we still know little about its genetic variation, infectivity, and the potential impact of variation on the Sf-rhabdovirus-host interaction. Here, we characterized Sf-rhabdoviruses from two widely used Sf cell lines to confirm and extend information on Sf-rhabdovirus variation. We then used our novel Sf-rhabdovirus-negative (Sf-RVN) Sf cell line to assess the infectivity of variants with and without a 320bp X/L deletion and found both established productive persistent infections in Sf-RVN cells. We also assessed their infectivity using heterologous insect and mammalian cell lines and found neither established productive persistent infections in these cells. These results are the first to directly demonstrate Sf-rhabdoviruses are infectious for Sf cells, irrespective of the X/L deletion. They also confirm and extend previous results indicating Sf-rhabdoviruses have a narrow host range.
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Affiliation(s)
| | - Donald L Jarvis
- GlycoBac, LLC, Laramie, WY 82072, USA; Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA.
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18
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CRISPR-Cas9 vectors for genome editing and host engineering in the baculovirus-insect cell system. Proc Natl Acad Sci U S A 2017; 114:9068-9073. [PMID: 28784806 DOI: 10.1073/pnas.1705836114] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The baculovirus-insect cell system (BICS) has been widely used to produce many different recombinant proteins for basic research and is being used to produce several biologics approved for use in human or veterinary medicine. Early BICS were technically complex and constrained by the relatively primordial nature of insect cell protein glycosylation pathways. Since then, recombination has been used to modify baculovirus vectors-which has simplified the system-and transform insect cells, which has enhanced its protein glycosylation capabilities. Now, CRISPR-Cas9 tools for site-specific genome editing are needed to facilitate further improvements in the BICS. Thus, in this study, we used various insect U6 promoters to construct CRISPR-Cas9 vectors and assessed their utility for site-specific genome editing in two insect cell lines commonly used as hosts in the BICS. We demonstrate the use of CRISPR-Cas9 to edit an endogenous insect cell gene and alter protein glycosylation in the BICS.
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19
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Hashimoto Y, Macri D, Srivastava I, McPherson C, Felberbaum R, Post P, Cox M. Complete study demonstrating the absence of rhabdovirus in a distinct Sf9 cell line. PLoS One 2017; 12:e0175633. [PMID: 28423032 PMCID: PMC5397025 DOI: 10.1371/journal.pone.0175633] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 03/29/2017] [Indexed: 12/26/2022] Open
Abstract
A putative novel rhabdovirus (SfRV) was previously identified in a Spodoptera frugiperda cell line (Sf9 cells [ATCC CRL-1711 lot 58078522]) by next generation sequencing and extensive bioinformatic analysis. We performed an extensive analysis of our Sf9 cell bank (ATCC CRL-1711 lot 5814 [Sf9L5814]) to determine whether this virus was already present in cells obtained from ATCC in 1987. Inverse PCR of DNA isolated from Sf9 L5814 cellular DNA revealed integration of SfRV sequences in the cellular genome. RT-PCR of total RNA showed a deletion of 320 nucleotides in the SfRV RNA that includes the transcriptional motifs for genes X and L. Concentrated cell culture supernatant was analyzed by sucrose density gradient centrifugation and revealed a single band at a density of 1.14 g/ml. This fraction was further analysed by electron microscopy and showed amorphous and particulate debris that did not resemble a rhabdovirus in morphology or size. SDS-PAGE analysis confirmed that the protein composition did not contain the typical five rhabdovirus structural proteins and LC-MS/MS analysis revealed primarily of exosomal marker proteins, the SfRV N protein, and truncated forms of SfRV N, P, and G proteins. The SfRV L gene fragment RNA sequence was recovered from the supernatant after ultracentrifugation of the 1.14 g/ml fraction treated with diethyl ether suggesting that the SfRV L gene fragment sequence is not associated with a diethyl ether resistant nucleocapsid. Interestingly, the 1.14 g/ml fraction was able to transfer baculovirus DNA into Sf9L5814 cells, consistent with the presence of functional exosomes. Our results demonstrate the absence of viral particles in ATCC CRL-1711 lot 5814 Sf9 cells in contrast to a previous study that suggested the presence of infectious rhabdoviral particles in Sf9 cells from a different lot. This study highlights how cell lines with different lineages may present different virosomes and therefore no general conclusions can be drawn across Sf9 cells from different laboratories.
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Affiliation(s)
- Yoshifumi Hashimoto
- Protein Sciences Corporation, Meriden, Connecticut, Unites States of America
| | - Daniel Macri
- Protein Sciences Corporation, Meriden, Connecticut, Unites States of America
| | - Indresh Srivastava
- Protein Sciences Corporation, Meriden, Connecticut, Unites States of America
| | - Clifton McPherson
- Protein Sciences Corporation, Meriden, Connecticut, Unites States of America
| | - Rachael Felberbaum
- Protein Sciences Corporation, Meriden, Connecticut, Unites States of America
| | - Penny Post
- Protein Sciences Corporation, Meriden, Connecticut, Unites States of America
| | - Manon Cox
- Protein Sciences Corporation, Meriden, Connecticut, Unites States of America
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20
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Kotin RM, Snyder RO. Manufacturing Clinical Grade Recombinant Adeno-Associated Virus Using Invertebrate Cell Lines. Hum Gene Ther 2017; 28:350-360. [DOI: 10.1089/hum.2017.042] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Robert M. Kotin
- Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts
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21
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Webster GR, Teh AYH, Ma JKC. Synthetic gene design-The rationale for codon optimization and implications for molecular pharming in plants. Biotechnol Bioeng 2016; 114:492-502. [PMID: 27618314 DOI: 10.1002/bit.26183] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 08/10/2016] [Accepted: 09/05/2016] [Indexed: 12/14/2022]
Abstract
Degeneracy in the genetic code allows multiple codon sequences to encode the same protein. Codon usage bias in genes is the term given to the preferred use of particular synonymous codons. Synonymous codon substitutions had been regarded as "silent" as the primary structure of the protein was not affected; however, it is now accepted that synonymous substitutions can have a significant effect on heterologous protein expression. Codon optimization, the process of altering codons within the gene sequence to improve recombinant protein expression, has become widely practised. Multiple inter-linked factors affecting protein expression need to be taken into consideration when optimizing a gene sequence. Over the years, various computer programmes have been developed to aid in the gene sequence optimization process. However, as the rulebook for altering codon usage to affect protein expression is still not completely understood, it is difficult to predict which strategy, if any, will design the "optimal" gene sequence. In this review, codon usage bias and factors affecting codon selection will be discussed and the evidence for codon optimization impact will be reviewed for recombinant protein expression using plants as a case study. These developments will be relevant to all recombinant expression systems; however, molecular pharming in plants is an area which has consistently encountered difficulties with low levels of recombinant protein expression, and should benefit from an evidence based rational approach to synthetic gene design. Biotechnol. Bioeng. 2017;114: 492-502. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Gina R Webster
- Molecular Immunology Unit, Institute for Infection and Immunity, St. George's University of London, SW17 0RE, London, UK
| | - Audrey Y-H Teh
- Molecular Immunology Unit, Institute for Infection and Immunity, St. George's University of London, SW17 0RE, London, UK
| | - Julian K-C Ma
- Molecular Immunology Unit, Institute for Infection and Immunity, St. George's University of London, SW17 0RE, London, UK
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Rhabdovirus-like endogenous viral elements in the genome of Spodoptera frugiperda insect cells are actively transcribed: Implications for adventitious virus detection. Biologicals 2016; 44:219-225. [PMID: 27236849 DOI: 10.1016/j.biologicals.2016.04.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/06/2016] [Accepted: 04/11/2016] [Indexed: 11/21/2022] Open
Abstract
Spodoptera frugiperda (Sf) cell lines are used to produce several biologicals for human and veterinary use. Recently, it was discovered that all tested Sf cell lines are persistently infected with Sf-rhabdovirus, a novel rhabdovirus. As part of an effort to search for other adventitious viruses, we searched the Sf cell genome and transcriptome for sequences related to Sf-rhabdovirus. To our surprise, we found intact Sf-rhabdovirus N- and P-like ORFs, and partial Sf-rhabdovirus G- and L-like ORFs. The transcribed and genomic sequences matched, indicating the transcripts were derived from the genomic sequences. These appear to be endogenous viral elements (EVEs), which result from the integration of partial viral genetic material into the host cell genome. It is theoretically impossible for the Sf-rhabdovirus-like EVEs to produce infectious virus particles as 1) they are disseminated across 4 genomic loci, 2) the G and L ORFs are incomplete, and 3) the M ORF is missing. Our finding of transcribed virus-like sequences in Sf cells underscores that MPS-based searches for adventitious viruses in cell substrates used to manufacture biologics should take into account both genomic and transcribed sequences to facilitate the identification of transcribed EVE's, and to avoid false positive detection of replication-competent adventitious viruses.
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